Overbanking?

[steve1811uk]

5 minutes ago, clockboy said:

That is a strange one. Do you get the same results with just a few winds. I have experienced over banking before which was because the mainspring was far too strong.

No, it only happens when the spring is fully wound and then gets overwound either on a brisk walk or artificially from a screwdriver winding the barrel.

[rodabod]

If it were a manual-wind then I’d say it maybe didn’t matter so much, but the automatic winding does lead you to a potential problem which you’ve obviously discovered. 
 

On the positive side, that’s still a great amplitude to be getting from a Seiko. 
 

I don’t think it would be unreasonable to modify the profile of the bridle slightly if you think the lubrication is correct. I have quoted De Carle’s book here which shows how it is done, though it should be fairly intuitive. 

[steve1811uk]

10 minutes ago, rodabod said:

If it were a manual-wind then I’d say it maybe didn’t matter so much, but the automatic winding does lead you to a potential problem which you’ve obviously discovered. 
 

On the positive side, that’s still a great amplitude to be getting from a Seiko. 
 

I don’t think it would be unreasonable to modify the profile of the bridle slightly if you think the lubrication is correct. I have quoted De Carle’s book here which shows how it is done, though it should be fairly intuitive. 

Thanks, I have actually just bought that very same book, Practical Watch Adjusting' so will have a study and have another try sometime. I just found out that replacement mainspring is recently obsolete at Cousins UK so I am short of options. I'm actually hoping that it will be ok in actual use but probably won't be based on the evidence.

[clockboy]

Maybe it is an over strength spring.

for Calibur 7005.      H 0.95.  Thickness 0.11.   Length 400.  Diameter 10

Worth checking for sure

 

[steve1811uk]

The problem appears to have been fixed by the barrel clean and grease with 8217. Went walking today for 2 s and then for another hour later in the day while monitoring for any time gains. The watch kept good time all day without any rapids gains. Will keep an eye on this to see if the fix is permanent.

[steve1811uk]

Well the issue has not been fixed. The watch still gains rapidly during a brisk walk when fully wound. I'm going to have to have another look at the barrel, mainspring and bridle. Any ideas how I can make the mainspring slip a bit more? Bridle shape perhaps?

Edited October 15, 2020 by steve1811uk

[rodabod]

Yes, you could adjust the bridle. See the drawing from DeCarle’s book regarding shaping it. I quoted it here once. 

[steve1811uk]

8 minutes ago, rodabod said:

Yes, you could adjust the bridle. See the drawing from DeCarle’s book regarding shaping it. I quoted it here once. 

Hi, I have two of his books now but couldn't find the drawing referred to. Steve.

[rodabod]

I recommend also buying “complicated watches and their repair”. Online forums are very helpful, but books like that are packed full of generally correct information and don’t have the “noise” tat you find on forums (such as questionable advice!). 
 

When you remove your spring, I’d measure the thickness out of interest, if you have a micrometer. 

[steve1811uk]

7 hours ago, rodabod said:

I recommend also buying “complicated watches and their repair”. Online forums are very helpful, but books like that are packed full of generally correct information and don’t have the “noise” tat you find on forums (such as questionable advice!). 
 

When you remove your spring, I’d measure the thickness out of interest, if you have a micrometer. 

Thank you. I will give that a go, make the bridle more curved.

[steve1811uk]

On 10/16/2020 at 7:07 AM, steve1811uk said:

Thank you. I will give that a go, make the bridle more curved.

Well I gave it a go today. Spring measured 0.95mm x 0.11mm. I made the bridle more curved and also got rid of a couple of minor kinks in the spring. Reworked spring has sweeping curves (dark green background). Reassembled using three small equally spaced dabs of 8217. Tested for slipping using a pin vice and observed slipping at 6.5 turns (wound 9 turns, waited ten seconds then counted the turns to unwind, that was 6.5). Refitted and all seems to be OK. Spring is slipping better than it was before and I am unable to induce any rebanking with a screwdriver winding the barrel. Steady amplitude DD is a bit lower though which I think is to be expected, 255 compared with the 270 it was before. Will see how it goes when worn.

Edited October 18, 2020 by steve1811uk

[DrG]

On 9/27/2020 at 4:32 AM, steve1811uk said:

Barrel wall was not worn. Cleaned, lubricated and reassembled by hand, 'tut tut'. After putting it back together I was still able to induce the rebanking with the screwdriver on the barrel. The only odd thing I did notice was that the outer turn did not follow the circular shape of the barrel wall perfectly. That came away from the wall a bit over about 120 degrees. It looked to be caused by the shape of the bridal that I don't think was curved enough to follow the barrel wall, too straight. That might be causing the spring to dig in a bit and not slip, that's all I can think of. I will see how the watch runs in use.

Hi! Judging by your description of the mainspring, it appears it is bent or misshapen. This could be a possible problem and I would suggest you change it. By your description of the watch sound (galloping horse) and the high amplitude, specially for a Seiko, I would  agree this sounds like rebanking. 
 

I would recommend trying to find a barrel complete assembly and replace, if you don’t have a mainspring winder. As trying to wind the mainspring by hand will likely damage it (specially the automatic ones with the bridle). I damaged many. 
 

cheers and best of luck! 

[steve1811uk]

5 hours ago, DrG said:

Hi! Judging by your description of the mainspring, it appears it is bent or misshapen. This could be a possible problem and I would suggest you change it. By your description of the watch sound (galloping horse) and the high amplitude, specially for a Seiko, I would  agree this sounds like rebanking. 
 

I would recommend trying to find a barrel complete assembly and replace, if you don’t have a mainspring winder. As trying to wind the mainspring by hand will likely damage it (specially the automatic ones with the bridle). I damaged many. 
 

cheers and best of luck! 

Thank you for your valuable input. The watch is still showing the undesirable behaviour of gaining time rapidly during a brisk walk when fully wound. I tested on the Timegrapher and after four or five side to side shakes the amplitude goes up rapidly to over 300 and then drops down to normal levels over the space of a minute. Anyway I think I might have been barking up the wrong tree. I remember when assembling the pallet that when I tested by pushing it side to side that sometimes it didn't stay in the direction it was nudged, it would bounce back off the banking pin. From reading some more I think this means there isn't enough lock and run to banking. I will look again when I get chance and report. I will be looking for banking pins that have been bent previously or a worn escape wheel (pallet fork is a new part). 

[JohnR725]

On 9/27/2020 at 2:31 AM, steve1811uk said:

No, it only happens when the spring is fully wound and then gets overwound either on a brisk walk or artificially from a screwdriver winding the barrel.

Your problem sounds like the example at the video below.

https://youtu.be/7KNTrHVD088

Then overbanking Is explained at the video below. Re-banking explained above is not the same as over banking explained below.

https://youtu.be/DxeM85XRTbU

 

[Nucejoe]

Just as a test, I would oil fork pivots+its jewel holes, to see if oscilator gains stability.

Does 7006 have banknig pins ot built in banking barriers?

Following oscilator's slowing down, if it keeps runing steady in static position, the escale wheel is Ok, sounds like you might have the joyful task of pallet adjust ahead or perhaps at the other end of the fork, guard pin so on.

Are you sure all side shake throughout the escape mech specially fork arbour are acceptable. 

Good luck.

[rodabod]

JohnR sometimes mentions that timegraphers are only an interpretation of what’s happening inside, and I think that applies here..... you mention that the timegrapher reports an amplitude of 300 degrees when shaken. Now, that is useful, but you have to understand where that figure is derived from. It’s ultimately based on the timing of the individual impulses sensed by the microphone. Shorter time duration would suggest the balance is swinging faster. Faster swinging means greater amplitude...... however, you introduce the subject of mis-locking. The escapement unlocking early would confuse the timegrapher to think the balance is moving faster/further. 
 

So, I agree with your suggestion to check the locking. Check the stones are securely fitted and not chipped (less likely on modern watches). Hopefully you’ll simply have misaligned adjustable banking pins, or perhaps a bent lever (unlikely). 

[steve1811uk]

1 hour ago, rodabod said:

JohnR sometimes mentions that timegraphers are only an interpretation of what’s happening inside, and I think that applies here..... you mention that the timegrapher reports an amplitude of 300 degrees when shaken. Now, that is useful, but you have to understand where that figure is derived from. It’s ultimately based on the timing of the individual impulses sensed by the microphone. Shorter time duration would suggest the balance is swinging faster. Faster swinging means greater amplitude...... however, you introduce the subject of mis-locking. The escapement unlocking early would confuse the timegrapher to think the balance is moving faster/further. 
 

So, I agree with your suggestion to check the locking. Check the stones are securely fitted and not chipped (less likely on modern watches). Hopefully you’ll simply have misaligned adjustable banking pins, or perhaps a bent lever (unlikely). 

Will be checking this at weekend. I'm pretty new to this hobby and thinking back to when I first put this watch together I don't think the escape wheel was locking on every tooth. At the time being new to the hobby I didn't think much of that. What I saw was that on some of the teeth the lever would move over in the way that I pushed but then immediately spring back (not locking). Pallet fork and balance complete are new, but the escape wheel is 50 years old. With what I know know I think it could have tooth wear and side shake, both contributing to the issue. I will order a new escape wheel in any case as they are still available. If I can solve this issue then I will have a very good accurate watch as taking the rebanking out of the equation the watch is running at 0 SPD and positional Delta is 4 seconds only across 6 positions. Fingers crossed.

[steve1811uk]

9 hours ago, JohnR725 said:

Your problem sounds like the example at the video below.

https://youtu.be/7KNTrHVD088

Then overbanking Is explained at the video below. Re-banking explained above is not the same as over banking explained below.

https://youtu.be/DxeM85XRTbU

 

Thanks, the title of the post is incorrect. I definitely mean rebanking.